{"id":"CVE-2018-12423","aliases":["DEBIAN-CVE-2018-12423","EUVD-2022-3580","GHSA-ch5v-fhg8-7gv9","PYSEC-2026-844","UBUNTU-CVE-2018-12423","USN-6076-1"],"status":"published","title":"Matrix Synapse Authorization Error","description":"In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no m.room.power_levels event in force.","severity":{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.01811,"percentile":0.78781,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"published":"2018-06-14T21:00:00Z","modified":"2026-10-24T10:30:26Z","fixes":[{"ecosystem":"PyPI","package":"matrix-synapse","fixed_in":["0.31.2"],"sources":["ghsa","osv"]},{"ecosystem":"Ubuntu:Pro:18.04:LTS","package":"matrix-synapse","fixed_in":["0.24.0+dfsg-1ubuntu0.1~esm1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.31.2"}]}]},{"source":"osv","ecosystem":"PyPI","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.31.2"}]}]},{"source":"osv","ecosystem":"PyPI","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.31.2"}]}]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.24.0+dfsg-1ubuntu0.1~esm1"}]}],"versions":["0.19.2+dfsg-6","0.24.0+dfsg-1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.24.0+dfsg-1ubuntu0.1~esm1"}]}],"versions":["0.19.2+dfsg-6","0.24.0+dfsg-1"],"bundled":7}],"products":[{"vendor":"matrix","product":"synapse"}],"references":[{"url":"https://matrix.org/blog/2018/06/14/security-update-synapse-0-31-2/","tags":["x_refsource_MISC","x_transferred","Vendor Advisory","advisory","report"]},{"url":"https://github.com/matrix-org/matrix-doc/issues/1304","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","advisory","web","report"]},{"url":"https://bugs.debian.org/901549","tags":["x_refsource_MISC","x_transferred","Mailing List","Third Party Advisory","advisory","web","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2018-12423","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-ch5v-fhg8-7gv9","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2018-12423","tags":["advisory"]},{"url":"https://github.com/matrix-org/synapse","tags":["package"]},{"url":"https://matrix.org/blog/2018/06/14/security-update-synapse-0-31-2","tags":["web"]},{"url":"https://pypi.org/project/matrix-synapse","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2018-12423","tags":["report"]},{"url":"https://github.com/matrix-org/synapse/pull/3397","tags":["report"]},{"url":"https://ubuntu.com/security/notices/USN-6076-1","tags":["advisory"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2018-12423","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2018-10657","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2018-12291","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2018-16515","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2019-5885","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2019-11842","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2019-18835","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2018-12423","description":"In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no m.room.power_levels event in force.","status":"published","published":"2018-06-14T21:00:00Z","modified":"2024-09-16T18:24:30.516Z","updated_at":"2026-11-02T14:35:06.679212Z"}],"euvd":[{"id":"EUVD-2022-3580","description":"In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no m.room.power_levels event in force.","status":"published","published":"2018-06-14T21:00:00Z","modified":"2024-09-16T18:24:30Z","updated_at":"2026-11-03T00:55:32.945265Z"}],"ghsa":[{"id":"GHSA-ch5v-fhg8-7gv9","title":"Matrix Synapse Authorization Error","description":"In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no `m.room.power_levels` event in force.","status":"published","published":"2022-05-13T01:49:35Z","modified":"2023-10-06T17:13:54Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T14:37:08.278692Z"}],"nvd":[{"id":"CVE-2018-12423","description":"In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no m.room.power_levels event in force.","status":"published","published":"2018-06-14T21:29:00.253Z","modified":"2026-06-17T01:37:45.907Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high","assessor":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"updated_at":"2026-11-02T14:04:29.837913Z"}],"osv":[{"id":"CVE-2018-12423","description":"In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no m.room.power_levels event in force.","status":"published","published":"2018-06-14T21:29:00.253Z","modified":"2026-10-24T10:30:26.8632692Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T15:44:07.934182Z"},{"id":"DEBIAN-CVE-2018-12423","description":"In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no m.room.power_levels event in force.","status":"withdrawn","published":"2018-06-14T21:29:00.253Z","modified":"2026-08-11T20:49:48.872660419Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T15:45:30.290351Z"},{"id":"GHSA-ch5v-fhg8-7gv9","title":"Matrix Synapse Authorization Error","description":"In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no `m.room.power_levels` event in force.","status":"published","published":"2022-05-13T01:49:35Z","modified":"2026-07-07T11:56:21.982919828Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T15:46:44.927642Z"},{"id":"PYSEC-2026-844","title":"Matrix Synapse Authorization Error","description":"In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no `m.room.power_levels` event in force.","status":"published","published":"2026-07-06T08:03:21.08032Z","modified":"2026-07-07T11:46:05.879609167Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T15:52:58.117212Z"},{"id":"UBUNTU-CVE-2018-12423","description":"In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no m.room.power_levels event in force.","status":"published","published":"2018-06-14T21:29:00Z","modified":"2026-02-04T04:25:01.892571Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T15:54:17.014176Z"},{"id":"USN-6076-1","title":"matrix-synapse vulnerabilities","description":"It was discovered that Synapse incorrectly handled certain inputs. If a\nuser or an automated system were tricked into opening a specially crafted\ninput file, a remote attacker could possibly use this issue to cause a\ndenial of service. (CVE-2019-18835, CVE-2018-12291, CVE-2018-10657)\n\nIt was discovered that Synapse incorrectly handled certain inputs. If a\nuser or an automated system were tricked into opening a specially crafted\ninput file, a remote attacker could possibly use this issue to hijack the\nsession. (CVE-2019-11842, CVE-2018-12423)\n\nIt was discovered that Synapse incorrectly handled certain inputs. If a\nuser or an automated system were tricked into opening a specially crafted\ninput file, a remote attacker could possibly use this issue to perform \nspoofing or user impersonation. (CVE-2019-5885, CVE-2018-16515)\n","status":"published","published":"2023-05-16T07:45:08Z","modified":"2026-02-10T04:43:07Z","updated_at":"2026-11-02T16:58:16.738762Z"}]}}